The present invention relates to a stepless tilting device for a large umbrella, such as beach or garden umbrella.
As is well known to those skilled in the art, relatively large umbrellas of the conventional beach, garden and lawn type incorporating tilting mechanisms are extremely difficult to operate due to their great weight, the force required to spread the canopy, and the force required to tilt the central rod. While umbrellas have been provided with operating devices employing mechanically advantageous mechanisms so as to reduce the required physical operating force, such devices have been subject to serious disadvantages. One problem common to the prior art devices was that of complex and expensive construction readily subject to malfunctioning. Another failing of the conventional umbrella-operating devices was the necessity for tedious and often skillful operating procedures, frequently consuming considerable time and requiring extraordinary dexterity.
U.S. Pat. No. 4,582,078 issued Apr. 15, 1986 to Ma entitled "Stepless Direction-Bending Device of the Central Rod for the Umbrella" discloses a stepless tilting mechanism which includes a carriage slidable on a hinged upper portion of the mast and which is moved axially against a spring bias after the umbrella has been opened. This arrangement allows the user to operate a linkage fast with the upper mast and which reacts against abutments provided on a fixed lower portion of the mast in order to effect tilting of the upper portion of the mast relative to the lower portion thereof.
The tilting mechanism made in accordance with the teaching of the Ma Patent is useful as it does not necessitate skillful operating procedures. However, the tilting mechanism of Ma still represents complex construction due to the use of links 24 and 25 (see FIG. 6) which are readily subject to deterioration and malfunctioning. In addition, the umbrella of Ma is not stable when it is placed in a vertical upright position due to the structure and combination of the links to other elements of the tilting mechanism.
The present invention is therefore intended to provide a stepless tilting device for an umbrella which obviates and mitigates the above-mentioned drawbacks.